private void ExtendedEuclide(int a, int b, out int x, out int y, out int d)
        {
            //a*x+b*y=nod(a,b)=d
            int q;//частное
            x = 1;
            y = 0;

            int x2 = 1;
            int x1 = 0;
            int y1 = 1;
            int y2 = 0;

            int r;//остаток
            while (b > 0)
            {
                q = a / b;
                //r = a - q * b;
                r = a % b;
                x = x2 - q * x1;
                y = y2 - q * y1;
                a = b;
                b = r;
                x2 = x1; x1 = x; y2 = y; y1 = y;
            }

            d = a;
            x = x2;
            y = y2;
        }